Re^4: Sort the file names a list

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Re^5: Sort the file names a list by bv (Friar) on Aug 31, 2009 at 17:11 UTC
I thought that it might, for a small set of inputs. The overhead of creating and populating the hash, as well as assignments to two new lexicals would only be overcome with a significantly larger data set. I wonder, though. Yep. Changing it to this: `{ my %cache; sub memoized { ( $cache{$a} \|\|= substr($a, -(19+20), 19) ) cmp ( $cache{$b} \|\|= substr($b, -(19+20), 19) ); } }` [download] gives a slight increase in speed (but my benchmarks are varying wildly right now. Maintaining ranking, but % differences are all over the board.) `Rate st memoized naive grt st 10281/s -- -6% -51% -54% memoized 10930/s 6% -- -48% -51% naive 20942/s 104% 92% -- -5% grt 22143/s 115% 103% 6% --` [download] `$,=' ';$\=',';$_=[qw,Just another Perl hacker,];print@$_;`	[reply] [d/l] [select]

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Re^5: Sort the file names a list
by bv (Friar) on Aug 31, 2009 at 17:11 UTC

I thought that it might, for a small set of inputs. The overhead of creating and populating the hash, as well as assignments to two new lexicals would only be overcome with a significantly larger data set.

I wonder, though. Yep. Changing it to this:

{
my %cache;
sub memoized {
    ( $cache{$a} ||= substr($a, -(19+20), 19) )
    cmp ( $cache{$b} ||= substr($b, -(19+20), 19) );
}
}
[download]

gives a slight increase in speed (but my benchmarks are varying wildly right now. Maintaining ranking, but % differences are all over the board.)

            Rate       st memoized    naive      grt
st       10281/s       --      -6%     -51%     -54%
memoized 10930/s       6%       --     -48%     -51%
naive    20942/s     104%      92%       --      -5%
grt      22143/s     115%     103%       6%       --
[download]

$,=' ';$\=',';$_=[qw,Just another Perl hacker,];print@$_;

[reply]
[d/l]
[select]